Denti:
By the way, you might ask them why they are not going for GBAS instead? Covers 50 precision approaches up to CAT IIIb capability within 25 NM around the station, one station costs less than a single VOR.
I know the answers to that one, at least for the FAA jurisdictions and the U.S. carriers.
1. The FAA is overwhelmed trying to get WAAS become an effective program for other than week-end light tin. Also, their rudder is broken on their NextGen "ship."
2. The airlines can't afford Boeing's or Airbus high, high prices for any avionics retrofits.